Electrostatic sensing method

ABSTRACT

An electrostatic sensing method is provided. An electrostatic sensing device comprising an electrostatic sensing module comprising a first electrostatic sensing element, and a control unit electrically connected to the electrostatic sensing module is provided. The first electrostatic sensing element is one-dimensional semiconducting linear structure. A direct voltage is applied to the first electrostatic sensing element. A sensed object with electrostatic charge is moved to the electrostatic sensing device in a distance near but not touching the first electrostatic sensing element. A resistance changed value of the first electrostatic sensing element is measured.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims all benefits accruing under 35 U.S.C. § 119 fromChina Patent Application No. 201410852141.6, filed on Dec. 31, 2014, inthe China Intellectual Property Office. Disclosures of theabove-identified applications are incorporated herein by reference.

FIELD

The present application relates to an electrostatic sensing device.

BACKGROUND

Following the advancement in recent years of various electronicapparatuses, such as mobile phones, car navigation systems and the like,toward high performance and diversification, there has been continuousgrowth in the number of electronic apparatuses equipped with opticallytransparent touch panels at the front of their respective displaydevices (e.g., liquid crystal panels). A user of any such electronicapparatus operates it by pressing or touching the touch panel with afinger, a pen, stylus, or another like tool while visually observing thedisplay device through the touch panel. Therefore, a demand exists fortouch panels that provide superior visibility and reliable operation.

With the rapid development of electronic apparatuses, some touch panelsneed to also recognize a hover event, i.e., an object (hand or touchpen) near but not touching the touch panel, and the position of thehover event at the touch panel. However, a sending device being used torecognize the hover event via electrostatic sensing was not reportedyet.

What is needed, therefore, is to provide an electrostatic sensing deviceand method for recognizing the hover event via electrostatic sensing.

BRIEF DESCRIPTION OF THE DRAWINGS

Implementations of the present technology will now be described, by wayof example only, with reference to the attached figures, wherein:

FIG. 1 is a schematic view of one embodiment of an electrostatic sensingdevice.

FIG. 2 a schematic view of one embodiment of an electrostatic sensingdevice.

FIG. 3 is an electron density of state distribution curve of carbonnanotube.

FIG. 4 is an electron density of state distribution curve of carbonnanotube under normal temperature measured by Scanning tunnelingspectroscopy (STS).

FIG. 5 is a side view of the electrostatic sensing device of FIG. 1.

FIG. 6 is a schematic view of one embodiment of an electrostatic sensingdevice.

FIG. 7 is a schematic view of one embodiment of an electrostatic sensingdevice.

FIG. 8 is a schematic view of one embodiment of an electrostatic sensingdevice.

FIG. 9 is a schematic view of one embodiment of an electrostatic sensingdevice.

DETAILED DESCRIPTION

It will be appreciated that for simplicity and clarity of illustration,where appropriate, reference numerals have been repeated among thedifferent figures to indicate corresponding or analogous elements. Inaddition, numerous specific details are set forth in order to provide athorough understanding of the embodiments described herein. However, itwill be understood by those of ordinary skill in the art that theembodiments described herein can be practiced without these specificdetails. In other instances, methods, procedures and components have notbeen described in detail so as not to obscure the related relevantfeature being described. The drawings are not necessarily to scale andthe proportions of certain parts may be exaggerated to better illustratedetails and features. The description is not to be considered aslimiting the scope of the embodiments described herein.

Several definitions that apply throughout this disclosure will now bepresented.

The term “substantially” is defined to be essentially conforming to theparticular dimension, shape or other word that substantially modifies,such that the component need not be exact. For example, substantiallycylindrical means that the object resembles a cylinder, but can have oneor more deviations from a true cylinder. The term “comprising” means“including, but not necessarily limited to”; it specifically indicatesopen-ended inclusion or membership in a so-described combination, group,series and the like.

The disclosure is illustrated by way of example and not by way oflimitation in the figures of the accompanying drawings in which likereferences indicate similar elements. It should be noted that referencesto “an” or “one” embodiment in this disclosure are not necessarily tothe same embodiment, and such references mean at least one.

Referring to FIG. 1, an electrostatic sensing device 100 according toone embodiment comprises an electrostatic sensing module 10 and acontrol unit 60 electrically connected to the electrostatic sensingmodule 10.

The electrostatic sensing module 10 comprises a substrate 14, a firstelectrostatic sensing element 124 having two opposite ends, and twofirst electrodes 122. The first electrostatic sensing element 124 andthe two first electrodes 122 are located on a surface of the substrate14. The two first electrodes 122 are separately located on andelectrically connected to the two opposite ends of the firstelectrostatic sensing element 124. The two first electrodes 122 areelectrically connected to the control unit 60 via conductive wire.

The substrate 14 can be flat or curved to support other elements. Thesubstrate 14 can be insulating and transparent. The substrate 14 can bealso opaque. The substrate 14 can be made of rigid materials such asglass, quartz, diamond, plastic or any other suitable material. Thesubstrate 14 can also be made of flexible materials such aspolycarbonate (PC), polymethyl methacrylate acrylic (PMMA), polyimide(PI), polyethylene terephthalate (PET), polyethylene (PE), polyetherpolysulfones (PES), polyvinyl polychloride (PVC), benzocyclobutenes(BCB), polyesters, or acrylic resin. A thickness of the substrate 14 canbe in a range from about 1 millimeter to about 1 centimeter. A shape andsize of the substrate 14 can be selected according to need. In oneembodiment, the substrate 14 is a flat quartz plate, the area of thesubstrate 14 is 2 centimeters×2 centimeters, the thickness of thesubstrate 14 is 2 millimeters.

The first electrostatic sensing element 124 is fixed on the surface ofthe substrate 14 via any means. In one embodiment, the firstelectrostatic sensing element 124 is fixed on the surface of thesubstrate 14 via an insulating adhesive. The insulating adhesive can becoated on whole surface of the first electrostatic sensing element 124.The insulating adhesive can only be located on portions of the firstelectrostatic sensing elements 124. The first electrostatic sensingelements 124 can be one-dimensional semiconducting linear structure withsingle crystal structure. A diameter of the one-dimensionalsemiconducting linear structure can be less than 100 nanometers. When asensed object with electrostatic charge near but does not touch thefirst electrostatic sensing element 124, the resistance of the firstelectrostatic sensing element 124 can be changed to produce a resistancesignal. The sensed object with any static charge can be regarded as thesensed object with electrostatic charge in this disclosure. In someembodiments, a user's finger(s) are as an example of the sensed objectwith electrostatic charge. The resistance change can be obtained bydetecting current change of the first electrostatic sensing element 124.

The one-dimensional semiconducting linear structure can be asemiconducting linear structure with larger length diameter ratio. Thelength diameter ratio of the one-dimensional semiconducting linearstructure is greater than 1000:1.

The one-dimensional semiconducting linear structure can be onesemiconducting graphene strip with a width of less than 10 nanometers, athickness of less than 5 nanometers, and a length of great than 1centimeter. The one-dimensional semiconducting linear structure can beone semiconducting silicon nanowire with a diameter of less than 5nanometers, and a length of greater than 1 centimeter. Theone-dimensional semiconducting linear structure can be one ultra longsingle walled carbon nanotube. The ultra long single walled carbonnanotube has a length greater than 1 centimeter, a diameter less than 5nanometers. The one-dimensional semiconducting linear structure can be afew-walled carbon nanotube with walls of from about two layers to aboutsix layers. In one embodiment, the few-walled carbon nanotube has two orthree layers wall. In one embodiment, the first electrostatic sensingelement 124 is a ultra long single walled carbon nanotube has a lengthabout 2 centimeters, a diameter about 2 nanometers.

Referring to FIG. 2, in one embodiment, the electrostatic sensing module10 can further comprise a plurality of the first electrostatic sensingelements 124 spaced and substantially parallel to each other, located onthe surface of the substrate 14. The two opposite ends of each of theplurality of the first electrostatic sensing elements 124 are separatelyelectrically connected together to the two first electrodes 122.

When a sensed object with electrostatic charge is near but does nottouch the one-dimensional semiconducting linear structure, theresistance of the one-dimensional semiconducting linear structure can bechanged. The sensed object can be recognized by a device because theresistance of the one-dimensional semiconducting linear structure ischanged. An electric field generated by static electricity of the sensedobject can easily affect Fermi surface moving of the one-dimensionalsemiconducting linear structure. Electric field outside theone-dimensional semiconducting linear structure would affect Fermisurface movement of the one-dimensional semiconducting linear structure.Conductivity of the one-dimensional semiconducting linear structuresignificantly changes with the Fermi surface movement of theone-dimensional semiconducting linear structure.

The one-dimensional semiconducting linear structure has excellentresponse to the electric field of the send object for below reasons.Almost the one-dimensional semiconducting linear structure can notconstitute an electric field shielding, and it can be completelyregulated by external electric field. While electric field applied on athree-dimensional conductive material can hardly affect internal of thethree-dimensional conductive material, because of the three-dimensionalconductive material having a strong surface shielding. Due to thequantum confinement effect, the electron density of states (DOS) ofone-dimensional material would have many singularities. While the Fermisurface is moving near the singularity, the electron density of stateswill dramatically changes. The dramatic changes of the electronicdensity of states would lead to the conductivity of the one-dimensionalsemiconducting linear structure significant changes.

Therefore, electrostatic can modulate the Fermi surface moving in thevicinity of the singularity in the one-dimensional semiconducting linearstructure, to get a significant change in the electrical conductivity ofthe semiconducting linear structure. Therefore, the sensed object withelectrostatic charge can be recognized by the one-dimensionalsemiconducting linear structure when the sensed object is near but doesnot touch the semiconducting linear structure. In order to realize thissensing static function, the distance between the Fermi surface and thesingularity of the one-dimensional semiconducting linear structureshould be within a specific range.

As shown in FIG. 3, the electron density of states distribution curve ofthe carbon nanotube have a lot of singularities. The electron density ofstates of the carbon nanotube takes great value at the point of thesingularity. Distribution of singularities is relatively symmetrical tozero energy. In an ideal state without making any doping, the Fermilevel locates on 0 eV place. The above properties are allone-dimensional semiconducting linear structure common characteristics.As previously mentioned, a sensitive response to the electrostaticrequires Fermi surface moving in the vicinity of the singularity ofone-dimensional semiconducting linear structure. So that there is a needto make the Fermi level to raise or decrease to the neighborhoodsingularity nearest to 0 eV. Referring to FIG. 4, in practice, due tothe thermal excitation, surface adsorption and interaction with thesurrounding environment, the singularities of one-dimensionalsemiconducting linear structure will be broadened into a half-heightpeak with a width L. The peaks are always to be buried because theoverlap of the peaks. But, the rising edge of peak singularity nearest 0eV is always present. To make the one-dimensional semiconducting linearstructure having sensitive response to electrostatic, the Fermi surfaceneeds to be fixed at a place with a distance to the singularity lessthan L/2. In practical applications, to obtain sensitive response toelectrostatic, through natural doping or manual doping, to make theenergy distance between the Fermi surface and the singularity of theone-dimensional semiconducting linear structure within a range of 30meV˜300 meV.

Carbon nanotubes prepared sample exposed to air, since the formation ofoxygen adsorbed p-type doped, the energy distance from the Fermi surfaceto singular points in the state density falls within 30˜300 meV,preferably 60 to fall within 100 meV. Therefore, thereby manual preparednatural carbon nanotubes have a sensitive electrostatic response.Graphene strips, semiconducting nanowires (e.g. silicon nanowires) canadsorb oxygen to form a p-type doping. A doping can also be used toadjust energy distance between the Fermi surface and the singular pointin the state density within a distance of 30˜300 meV.

When the sensed object with electrostatic charge nears but does nottouch the one-dimensional material semiconducting linear structure, theFermi level of the one-dimensional semiconducting linear structure wouldbe modulated, the corresponding electron density of states will change,and the conductivity will change consequently. Therefore, whenconsidering the sensitivity of the process, it is needed to focus on twothings: first, modulation efficiency of the sensed object to the Fermilevel of the one-dimensional semiconducting linear structure; second,the change rate of the density of states with the Fermi level moving ofthe one-dimensional semiconducting linear structure.

With respect to the first point, this is strongly influenced by thesubstrate material, the surface adsorption and other environmentalfactors. It is impossible to quantitatively determine the modulationefficiency of the sensed object to the Fermi level of theone-dimensional semiconducting linear structure theoretically. Themodulation efficiency of the sensed object to the Fermi level of theone-dimensional semiconducting linear structure can only be obtainedfrom experimental measurements. Silica, for example, a sample of thesilica substrate, the modulation efficiency is measured as 4×10⁻⁵. Thesecond point is a requirement about the one-dimensional semiconductinglinear structure, which requires the absolute value of(dσ/dE_(F))/(σ/E_(F)) greater than 10⁻¹, or greater than 10⁻³ (σ is theconductivity of the one-dimensional semiconducting linear structure,E_(F) is the Fermi surface location of the one-dimensionalsemiconducting linear structure). In this condition, when the sensedobjection is close to the one-dimensional semiconducting linearstructure, the conductivity change is not less than 10% in favor tosignal detection.

When using carbon nanotubes with the diameter distribution of 2-3 nm(carbon nanotubes are located on a silica substrate), the conductivityof the carbon nanotubes reduce by half (dσ/σ˜½), when a sensed objectwith electrostatic charge 1000V is near the carbon nanotubes at a place0.5 centimeter far from the carbon nanotubes. The modulation efficiencyis measured as 4×10⁻⁵, dE_(F)˜40 meV. The E_(F) of the carbon nanotubesis E_(F)˜150 meV. Thus, the absolute value of (dσ/dE_(F))/(σ/E_(F)) ofthe carbon nanotube is about 2. The graphene strips, the semi-conductivenano-wires can satisfy the requirement of (dσ/dE_(F))/(σ/E_(F)) isgreater than 10⁻¹, or greater than 10⁻³. If it is just to achieve aqualitative sense the presence or absence of the sensed object withstatic electricity, (dσ/dE_(F)/(σ/E_(F)) of one-dimensionalsemiconducting linear structure is greater than 10⁻³. If it is toquantify the amount of sensing electrostatic or sense the position ofthe sensed object with static electricity, (dσ/dE_(F)/(σ/E_(F)) ofone-dimensional semiconducting linear structure is greater than 10⁻¹.

One single walled carbon nanotube or a single few-walled carbon nanotubeis a quasi-one-dimensional structure. The smaller the diameter of thequasi-one-dimensional structure is, the density of states (DOS) of thequasi-one-dimensional structure is greater. The greater the DOS of thequasi-one-dimensional structure is, the shielding effect of thequasi-one-dimensional structure is smaller. The smaller the shieldingeffect of the quasi-one-dimensional structure is, the sensibility ofsensing static electricity of the quasi-one-dimensional structure isgreater. Therefore, the smaller the diameter of the single walled carbonnanotube or the few-walled carbon nanotube is, the sensibility ofsensing position coordinate of the sensed object is greater.

The diameter of the single walled carbon nanotube or the few-walledcarbon nanotube can be less than about 5 nanometers. In one embodiment,the diameter of the single walled carbon nanotube or the few-walledcarbon nanotube is in a range from about 2 nanometers to about 5nanometers. The ultra long single walled carbon nanotube or few-walledcarbon nanotube can have a length greater than 1 centimeter. In oneembodiment, the first electrostatic sensing element 124 is single walledcarbon nanotubes or few-walled carbon nanotubes with diameter of about 2nanometers and length of about 2 centimeters. The single walled carbonnanotubes or few-walled carbon nanotubes can be made by a known methodof adopting a “kite-mechanism”. An example of the “kite-mechanism” isdisclosed in Publication No. US20130252405A1.

The two first electrodes 122 can be made of a conductive material, suchas metal, conductive polymer, conductive adhesive, metallic carbonnanotubes, or indium tin oxide (ITO). The two first electrodes 122 canbe made by a method such as screen printing, chemical vapor deposition,or magnetron sputtering. In one embodiment, the material of the twofirst electrodes 220 is ITO.

The control unit 60 is configured to apply a direct voltage to the firstelectrostatic sensing element 124 and measure a current/resistance ofthe first electrostatic sensing element 124. The control unit 60comprises a circuit control module 62, a resistance measuring module 64and a switch 66. The circuit control module 62, the resistance measuringmodule 64 and the switch 66 are electrically connected to the two firstelectrodes 122. It is understood that, the amount of the switch 66depends on the amount of the first electrostatic sensing element 124.

A method of sensing electrostatic using the electrostatic sensing device100, comprises steps of:

S1, providing the electrostatic sensing device 100;

S2, applying a direct voltage to the first electrostatic sensing element124;

S3, measuring the resistance changed value of the first electrostaticsensing element 124 in response to the sensed object, with electrostaticcharge, being near but not making contact with the first electrostaticsensing element 124, wherein a distance between the sensed object andthe first electrostatic sensing element 124 is less than 0.5 centimeter.

In step S1, the electrostatic sensing device 100 can be used as a simpleswitch or electrostatic sensing used as a switch, it can also be usedwith other electronic components, thereby controlling the opening andclosing of the circuit.

In step S2, the circuit control module 62 applies a direct voltage tothe first electrostatic sensing element 124. In step S3, the sensedobject with electrostatic charge refers to the object itself with anelectrostatic charge, which can produce an electrostatic field. Theobject with any static charge can be regarded as the sensed object withelectrostatic charge in this disclosure. In some embodiments, a user'sfinger(s) are as an example of the sensed object with electrostaticcharge.

In step S3, the resistance measuring module 64 can measure thecurrent/resistance of the first electrostatic sensing element 124. Acurrent/resistance changed value of the first electrostatic sensingelement 124 is proportional to a distance between the sensed object andthe first electrostatic sensing element 124. The smaller the distancebetween the sensed object and the first electrostatic sensing element124 is, the current/resistance changed value of the first electrostaticsensing element 124 is greater. The current/resistance changed value canbe measured by the resistance measuring module 64.

Furthermore, the electrostatic sensing device 100 can measure thedistance between the sensed object and the first electrostatic sensingelement 124. According to the resistance changed value of the firstelectrostatic sensing element 124 when the sensed object near but doesnot touch the first electrostatic sensing element 124, the distancebetween the sensed object and the first electrostatic sensing element124 can be measured. In application, a threshold value of the resistancechanged value can be set. The threshold value of the resistance changedvalue corresponds to a setting threshold distance between the sensedobject and the first electrostatic sensing element 124. Therefore, whenthe sensed object is moved to the place which meets the settingthreshold distance from the first electrostatic sensing element 124, theelectrostatic sensing device 100 would send a signal which enables afunction of switches. Further, the threshold value of the resistancechanged value can be used to control the impact of noise, such as staticinterference outside. Only when the resistance changed value of thefirst electrostatic sensing element 124 reaches the threshold, theelectrostatic sensing device 100 will send a signal to achieve function.

Referring to FIG. 5, the electrostatic sensing device 100 can furthercomprise an insulating protecting layer 80 located on the substrate 14to protect the electrostatic sensing module 10. The first electrostaticsensing element 124 and the first electrode 122 are covered by theinsulating protecting layer 80. The material of the insulatingprotecting layer 80 is insulating and transparent, such as polyethylene(PE), polycarbonate (PC), polyethylene terephthalate (PET), polymethylmethacrylate acrylic (PMMA), or thin glass.

Referring to FIG. 6, an electrostatic sensing device 200 according toone embodiment comprises an electrostatic sensing module 20 and acontrol unit 60 electrically connected to the electrostatic sensingmodule 20.

The electrostatic sensing module 20 comprises a substrate 14, aplurality of first electrostatic sensing elements 124, and a pluralityof first electrodes 122. The plurality of first electrostatic sensingelements 124 and the plurality of first electrodes 122 are located on asurface of the substrate 14. The plurality of first electrostaticsensing elements 124 is spaced and substantially parallel to each otherin same interval on a same plane. Each two first electrodes 122 of theplurality of first electrodes 122 are according to one firstelectrostatic sensing element 124 of the plurality of firstelectrostatic sensing elements 124. Each two first electrodes 122 of theplurality of first electrodes 122 are separately located on andelectrically connected to two opposite sides of one of the plurality offirst electrostatic sensing elements 124.

In FIGS. 6-9, a first direction X and a second direction Y,perpendicular to the first direction X, are defined in the surface ofthe substrate 14. A third direction Z, perpendicular to the surface ofthe substrate 14, is also defined and shown in FIGS. 6-9. The thirddirection Z is perpendicular to a plane defined by the first direction Xand the second direction Y. The X, Y, Z define a coordination system. InFIG. 5 according to one embodiment, the plurality of first electrostaticsensing elements 124 extends along the first direction X, and isarranged along the second direction Y with same interval. A distancebetween two adjacent first electrostatic sensing elements 124 can beselected according to resolution ratio. The distance between twoadjacent first electrostatic sensing elements 124 can be in a range fromabout 2 millimeters to about 2 centimeters. In one embodiment, thedistance between two adjacent first electrostatic sensing elements 124is about 3 millimeters. The X, Y, Z define a coordination system in 3dimensional.

The plurality of first electrostatic sensing elements 124 are labeled byX_(m) according to an arranging order of the plurality of firstelectrostatic sensing elements 124. The m is a positive integer. Theplurality of first electrostatic sensing elements 124 are electricallyconnected to the control unit 60 by conductive wires. Thus, when thedirect voltage is applied to the plurality of first electrostaticsensing elements 124, the currents of the plurality of firstelectrostatic sensing elements 124 are detected. When the sensed objectis near but not touching the plurality of first electrostatic sensingelements 124, the current/resistance change can also be detected.

The control unit 60 is configured to apply a direct voltage to each ofthe plurality of first electrostatic sensing elements 124 and measure acurrent/resistance of each of the plurality of first electrostaticsensing elements 124. The control unit 60 comprises a circuit controlmodule 62, a resistance measuring module 64 and a plurality of switches66. It is understood that, the number of the switches 66 is same asnumber of the first electrostatic sensing element 124.

Each one of the plurality of first electrostatic sensing elements 124 isconnected to one switch 66 connected to the control unit 60. The circuitcontrol module 62 can apply direct voltage to each one of the pluralityof first electrostatic sensing elements 124. The resistance measuringmodule 64 can measure the current/resistance of each one of theplurality of first electrostatic sensing elements 124.

The electrostatic sensing device 200 can be used to sense a location ofthe sensed object along the second direction Y when the sensed object isnear but does not touch the electrostatic sensing module 20. A method ofsensing electrostatic using the electrostatic sensing device 200,comprises steps of:

S10, providing the electrostatic sensing device 200;

S20, applying a direct voltage to the plurality of first electrostaticsensing elements 124; and

S30, measuring the resistance changed values of the plurality of firstelectrostatic sensing elements 124 in response to the sensed object,with electrostatic charge, being near but not making contact with theplurality of first electrostatic sensing elements 124, wherein adistance between the sensed object and the plurality of firstelectrostatic sensing elements 124 is less than 0.5 centimeter.

In step S30, when the sensed object with electrostatic charge is movedto the electrostatic sensing module 20 in a distance near but nottouching the plurality of first electrostatic sensing elements 124, theresistance changed values of the plurality of first electrostaticsensing elements 124 can be measured by the resistance measuring module64.

The resistance changed values of the plurality of first electrostaticsensing elements 124 are defined as RXm. Therefore, m resistance changedvalues can be obtained, such as RX₁, RX₂, RX₃, . . . , RXm.

The resistance changed value of the first electrostatic sensing element124 that is closest to the sensed object is the largest. The location ofthe first electrostatic sensing element 124 closest to the sensed objectcan be known according to the largest resistance changed value of firstelectrostatic sensing element 124. Thus, the position of the sensedobject in the second direction Y can be known, and Y coordinate of thesensed object can be known.

The electrostatic sensing device 200 can distinguish the moving of touchpen or gesture. The moving of touch pen or gesture can achievetransmission of instruction, and accordingly, achieve operation ofelectrical device including the electrostatic sensing device 200. Theelectrical device can be display or switch. A Z direction of position ofthe sensed object can be determined by analyzing signal strength.

According to the resistance changed value of the first electrostaticsensing element 124 when the sensed object nears but does not touch thefirst electrostatic sensing element 124, the distance along Z betweenthe sensed object and the first electrostatic sensing element 124 can bemeasured. In the application, a threshold value of the resistancechanged value can be set. The threshold value of the resistance changedvalue is proportional to a setting threshold distance between the sensedobject and the first electrostatic sensing element 124. Therefore, whenthe sensed object is moved to a place to the first electrostatic sensingelement 124 to meet the setting threshold distance, the electrostaticsensing device 200 would send a signal which enables a function ofswitches. Further, the threshold value of the resistance changed valuecan be used to control the impact of noise, such as static interferenceoutside. Only when the resistance changed value of the firstelectrostatic sensing element 124 reaches the threshold value, theelectrostatic sensing device 200 will send a signal to achieve function.

The electrostatic sensing device 200 could distinguish gesture by stepsof:

S110, providing the electrostatic sensing device 200;

S120, applying a direct voltage to the plurality of first electrostaticsensing elements 124; and

S130, measuring the resistance changed values of the plurality of firstelectrostatic sensing elements 124 in response to the sensed object,with electrostatic charge, moving to the plurality of firstelectrostatic sensing elements 124 along the second direction Y, whereina distance between the sensed object and the plurality of firstelectrostatic sensing element s124 is less than 0.5 centimeter.

In step S130, the moving tracks or direction of the sensed object can bemeasured by the locations of the first electrostatic sensing elements124 with the largest resistance changed values. The sensed objection ismoved from the first electrostatic sensing elements 124 with the firstlargest resistance changed value to the first electrostatic sensingelements 124 with the last largest resistance changed value.

It is understood that the electrostatic sensing device 200 can furthercomprise the insulating protecting layer 80 shown in FIG. 5 to protectthe electrostatic sensing module 20.

Referring to FIG. 7, an electrostatic sensing device 300 according toone embodiment includes an electrostatic sensing module 30 and a controlunit 60 electrically connected to the electrostatic sensing module 30.The electrostatic sensing device 300 has same function as theelectrostatic sensing device 200. The electrodes connection of theelectrostatic sensing device 300 is different to the electrostaticsensing device 200.

The electrostatic sensing module 30 comprises a substrate 14, aplurality of first electrostatic sensing elements 124, a plurality offirst electrodes 122 and a third electrode 120. The plurality of firstelectrostatic sensing elements 124, the plurality of first electrodes122 and the third electrode 120 are located on a surface of thesubstrate 14. The plurality of first electrostatic sensing elements 124is spaced and substantially parallel to each other with same interval.Each of the first electrostatic sensing elements 124 has two oppositeends. One end of each of the plurality of first electrostatic sensingelements 124 is electrically connected to one of the plurality of firstelectrodes 122. Another end of each of the plurality of firstelectrostatic sensing elements 124 is electrically connected together tothe third electrodes 120. The plurality of first electrostatic sensingelements 124 extends along the first direction X. The third electrode120 extends along the second direction Y. The third electrode 120 ismade of same material as the plurality of first electrodes 122.

Each one of the plurality of first electrostatic sensing elements 124 isconnected to one switch 66 connected to the control unit 60. The circuitcontrol module 62 can apply a direct voltage to each one of theplurality of first electrostatic sensing elements 124 simultaneously orin sequence. The resistance measuring module 64 can measure thecurrent/resistance of each one of the plurality of first electrostaticsensing elements 124. The electrostatic sensing device 300 has a samefunction as the electrostatic sensing device 200.

Referring to FIG. 8, an electrostatic sensing device 400 according toone embodiment comprises an electrostatic sensing module 40 and acontrol unit 60 electrically connected to the electrostatic sensingmodule 40.

The electrostatic sensing module 40 comprises a substrate 14, aplurality of first electrostatic sensing elements 124, a plurality ofsecond electrostatic sensing elements 164, a plurality of firstelectrodes 122, and a plurality of second electrodes 162. The pluralityof first electrostatic sensing elements 124, the plurality of secondelectrostatic sensing elements 164, the plurality of first electrodes122, and the plurality of second electrodes 162 are located on a surfaceof the substrate 14. The plurality of first electrostatic sensingelements 124 and the plurality of second electrostatic sensing elements164 are made same materials. The plurality of first electrostaticsensing elements 124 and the plurality of second electrostatic sensingelements 164 are intersected with each other, to form a plurality ofgrids. The plurality of first electrostatic sensing elements 124 and theplurality of second electrostatic sensing elements 164 are electricallyinsulated from each other. In one embodiment, the plurality of firstelectrostatic sensing elements 124 and the plurality of secondelectrostatic sensing elements 164 are arranged in different planes.Each first electrostatic sensing element 124 has a first end and asecond end opposite to the first end. The first end is electricallyconnected to one first electrode 122, and the second end is electricallyconnected to another one first electrode 122. Each second electrostaticsensing element 164 has a third end and a forth end opposite to thethird end. The third end is electrically connected to one secondelectrode 162, and the forth end is electrically connected to anotherone second electrode 162.

The plurality of first electrostatic sensing elements 124 extends alongthe first direction X. The plurality of first electrostatic sensingelements 124 is spaced from each other with same interval andsubstantially parallel to each other. The plurality of secondelectrostatic sensing elements 164 extends along the second direction Y.The plurality of second electrostatic sensing elements 164 is spacedfrom each other with same interval and substantially parallel to eachother. The plurality of first electrostatic sensing elements 124 can belocated on the surface of the substrate 14, and the plurality of secondelectrostatic sensing elements 164 can be located on the plurality offirst electrostatic sensing elements 124. A distance between twoadjacent first electrostatic sensing elements 124 and a distance betweentwo adjacent second electrostatic sensing elements 164 can be selectedaccording to resolution ratio. A distance between two adjacent firstelectrostatic sensing elements 124 and a distance between two adjacentsecond electrostatic sensing elements 164 can be in a range from about 2millimeters to about 2 centimeters.

The plurality of first electrostatic sensing elements 124 and theplurality of second electrostatic sensing elements 164 can be adhered onthe surface of the substrate 14 by an insulating adhesive. Theinsulating adhesive can be located on whole surface of the plurality offirst electrostatic sensing elements 124, and the plurality of secondelectrostatic sensing elements 164 can be located on the insulatingadhesive. The insulating adhesive can only be located on portions of theplurality of first electrostatic sensing elements 124 intersected withthe plurality of second electrostatic sensing elements 164. In oneembodiment, the insulating adhesive is only located on the portions ofthe plurality of first electrostatic sensing elements 124 intersectedwith the plurality of second electrostatic sensing elements 164.

The plurality of first electrodes 122 and the plurality of secondelectrodes 162 can be made of a conductive material, such as metal,conductive polymer, conductive adhesive, metallic carbon nanotubes, orindium tin oxide (ITO). The plurality of first electrodes 122 and theplurality of second electrodes 162 can be made by a method such asscreen printing, chemical vapor deposition, or magnetron sputtering. Inone embodiment, the material of the plurality of first electrodes 122and the plurality of second electrodes 162 is ITO.

The control unit 60 comprises a circuit control module 62, a resistancemeasuring module 64, and a plurality of switches 66. The control unit 60can be electrically connected to the plurality of first electrodes 122and the plurality of second electrodes 162 by conductive wire, in orderto electrically connect the control unit 60 to the electrostatic sensingmodule 40. Each of the plurality of second electrostatic sensingelements 164 is electrically connected to one switch 66. Each of theplurality of first electrostatic sensing elements 124 is electricallyconnected to one switch 66.

The circuit control module 62 can be electrically connected to theresistance measuring module 64 by conductive wire. A direct voltage canbe applied to the plurality of first electrostatic sensing elements 124and the plurality of second electrostatic sensing elements 164 by thecircuit control module 62. The resistance measuring module 64 can detectthe currents of the plurality of first electrostatic sensing elements124 and the plurality of second electrostatic sensing elements 164.Thus, the resistance variations of the plurality of first electrostaticsensing elements 124 and the plurality of second electrostatic sensingelements 164 can be measured.

The plurality of first electrostatic sensing elements 124 are labeled byX_(m) according to an arranging order of the plurality of firstelectrostatic sensing elements 124. The m is a positive integer. Theplurality of first electrostatic sensing elements 124 are electricallyconnected to the resistance measuring module 64 by conductive wires.Thus, when the direct voltage is applied to the plurality of firstelectrostatic sensing elements 124, the currents of the plurality offirst electrostatic sensing elements 124 are detected.

The plurality of second electrostatic sensing elements 164 are labeledby Y_(n) according to an arranging order of the plurality of secondelectrostatic sensing elements 164. The n is a positive integer. Theplurality of second electrostatic sensing elements 164 are electricallyconnected to the control unit 60 by conductive wires. Thus, when thedirect voltage is applied to the plurality of second electrostaticsensing elements 164, the currents of the plurality of secondelectrostatic sensing elements 164 are detected.

The direct voltages can be simultaneously applied by the circuit controlelement 440, when the sensed object nears but not touch the surface ofthe substrate 14, currents of the plurality of first electrostaticsensing elements 124 and the plurality of second electrostatic sensingelements 164 will change because of influence of band gap structure inthe single walled carbon nanotube or the few-walled carbon nanotube asexplained before. The resistance measuring module 64 can detect thecurrent changes of the plurality of first electrostatic sensing elements124 along the second direction Y and the first direction X. Theresistance measuring module 64 can detect the current changes of theplurality of second electrostatic sensing elements 164 along the seconddirection Y and the first direction X.

The resistance changed values of the plurality of first electrostaticsensing elements 124 are defined as RXm. Therefore, m resistance changedvalues can be obtained, such as RX₁, RX₂, RIX₃, . . . , RXm. Theresistance changed values of the plurality of second electrostaticsensing elements 164 are defined as RYn. Thus, n resistance changedvalues can be obtained, such as RY₁, RY₂, RY₃, . . . , RYn.

The resistance changed value of the first electrostatic sensing element124 closest to the sensed object is the largest. The first electrostaticsensing element 124 closest to the sensed object can be known accordingto the largest resistance changed value of first electrostatic sensingelement 124. Thus, the distance between the sensed object and the firstelectrostatic sensing element 124 closest to the sensed object can beknown, and accordingly, the position of the sensed object in the seconddirection Y can be known, and Y coordinate of the sensed object can beknown.

The resistance changed value of the second electrostatic sensing element164 closest to the sensed object is the largest. The secondelectrostatic sensing element 164 closest to the sensed object can beknown according to the largest resistance changed value of secondelectrostatic sensing element 164. Thus, the distance between the sensedobject and the second electrostatic sensing element 164 closest to thesensed object can be known, and accordingly, the position of the sensedobject in the second direction X can be known, and X coordinate of thesensed object can be known. The position of the sensed object can beobtained according to Y coordinate and X coordinate of the sensedobject. An electrical device comprises the electrostatic sensing device400 can be controlled by the position coordinates of the sensed object,after determining the position coordinates of the sensed object.

The electrostatic sensing device 400 can distinguish the moving of touchpen or gesture. The moving of touch pen or gesture can achievetransmission of instruction, and accordingly, achieve operation ofelectrical device including the electrostatic sensing device 400. Theelectrical device can be display or switch. Multi-touch control andmulti-hover control can be achieved by adjusting driving mode andcomputational method. A Z direction of position of the sensed object canbe determined by analyzing signal strength.

A method for detecting the sensed object of the electrostatic sensingdevice 400 comprises steps of:

S100, providing the electrostatic sensing device 400;

S200, applying a direct voltage to the plurality of first electrostaticsensing elements 124, and the plurality of second electrostatic sensingelements 164; and

S300, measuring the resistance changed values of the plurality of firstelectrostatic sensing elements 124 and the plurality of secondelectrostatic sensing elements 164 in response to the sensed object,with electrostatic charge, being near but not making contact with theplurality of first electrostatic sensing elements 124 and the pluralityof second electrostatic sensing elements 164, wherein a distance betweenthe sensed object and the plurality of first electrostatic sensingelements 124 and the plurality of second electrostatic sensing elements164 is less than 0.5 centimeter.

In step S200, the direct voltage can be applied to the plurality offirst electrostatic sensing elements 124 and the plurality of secondelectrostatic sensing elements 164 simultaneously. The direct voltagecan also be applied to the plurality of first electrostatic sensingelements 124 in sequence. The direct voltage can also be applied to theplurality of second electrostatic sensing elements 164 in sequence.

Referring to FIG. 9, an electrostatic sensing device 500 according toone embodiment comprises an electrostatic sensing module 50 and acontrol unit 60 electrically connected to the electrostatic sensingmodule 50. The electrostatic sensing device 500 almost has samestructure and function as the electrostatic sensing device 400, exceptthe electrodes locations.

The electrostatic sensing module 50 comprises a substrate 14, aplurality of first electrostatic sensing elements 124, a plurality ofsecond electrostatic sensing elements 164, a plurality of firstelectrodes 122, a plurality of second electrodes 162, a third electrode120 and a forth electrode 160. The plurality of first electrostaticsensing elements 124, the plurality of second electrostatic sensingelements 164, the plurality of first electrodes 122, the plurality ofsecond electrodes 162, the third electrode 120 and the forth electrode16 are located on a surface of the substrate 14. The third electrode 120and the forth electrode 160 are made of same material. The plurality offirst electrostatic sensing elements 124 and the plurality of secondelectrostatic sensing elements 164 are intersected with each other, toform a plurality of grids. The plurality of first electrostatic sensingelements 124 and the plurality of second electrostatic sensing elements164 are electrically insulated from each other. In one embodiment, theplurality of first electrostatic sensing elements 124 and the pluralityof second electrostatic sensing elements 164 are arranged in differentplanes. Each first electrostatic sensing element 124 has a first end anda second end opposite to the first end. The first end is electricallyconnected to one first electrode 122, and the second ends of theplurality of first electrostatic sensing elements 124 are electricallyconnected together to the third electrode 120. Each second electrostaticsensing element 164 has a third end and a forth end opposite to thethird end. The third end is electrically connected to one secondelectrode 162, and the forth ends of the plurality of secondelectrostatic sensing elements 164 are electrically connected togetherto the forth electrode 160.

The embodiments shown and described above are only examples. Even thoughnumerous characteristics and advantages of the present technology havebeen set forth in the foregoing description, together with details ofthe structure and function of the present disclosure, the disclosure isillustrative only, and changes may be made in the detail, including inmatters of shape, size and arrangement of the parts within theprinciples of the present disclosure up to, and including, the fullextent established by the broad general meaning of the terms used in theclaims.

Additionally, it is also to be understood that the above description andthe claims drawn to a method may include some indication in reference tocertain steps. However, the indication used is only to be viewed foridentification purposes and not as a suggestion as to an order for thesteps.

What is claimed is:
 1. An electrostatic sensing method, comprising:providing an electrostatic sensing device comprising an electrostaticsensing module comprising a first electrostatic sensing element, and acontrol unit electrically connected to the electrostatic sensing module,wherein the first electrostatic sensing element is just onesingle-walled carbon nanotube or just one few-walled carbon nanotubewith two walls to six walls; applying a direct voltage to the firstelectrostatic sensing element; and measuring a resistance changed valueof the first electrostatic sensing element in response to a sensedobject, with electrostatic charge, being near but not making contactwith the first electrostatic sensing element, wherein a distance betweenthe sensed object and the first electrostatic sensing element is lessthan 0.5 centimeter.
 2. The method as claimed in claim 1, wherein theresistance changed value is proportional to the distance.
 3. The methodas claimed in claim 2, wherein a threshold value of the resistancechanged value is set, when the resistance changed value is greater thanthe threshold value, the resistance changed value is recognized.
 4. Themethod as claimed in claim 1, wherein the control unit is configured toapply the direct voltage to the first electrostatic sensing element andmeasure a current or resistance of the first electrostatic sensingelement.
 5. The method as claimed in claim 1, wherein a ratio of lengthto diameter of the just one single walled carbon nanotube or a ratio oflength to diameter of the just one few-walled carbon nanotube is greaterthan 1000:1.
 6. The method as claimed in claim 1, wherein a length ofthe just one single walled carbon nanotube is greater than 1 centimeterand a diameter of the just one single walled carbon nanotube is lessthan 5 nanometers.
 7. The method as claimed in claim 1, wherein theelectrostatic sensing module further comprises a substrate, and the justone single walled carbon nanotube or just one few-walled carbon nanotubewith two walls to six walls is fixed on a surface of the substrate viaan insulating adhesive.
 8. The method as claimed in claim 7, wherein amaterial of the substrate is polycarbonate (PC), polymethyl methacrylateacrylic (PMMA), polyimide (PI), polyethylene terephthalate (PET),polyethylene (PE), polyether polysulfones (PES), polyvinyl polychloride(PVC), benzocyclobutenes (BCB), polyesters, or acrylic resin.
 9. Themethod as claimed in claim 1, wherein the first electrostatic sensingelement comprises two opposite ends, the electrostatic sensing modulefurther comprises two first electrodes separately located on andelectrically connected to the two opposite ends of the firstelectrostatic sensing element.
 10. The method as claimed in claim 4,wherein the control unit comprises a circuit control module, aresistance measuring module and a switch.
 11. An electrostatic sensingmethod for detecting a sensed object, comprising steps of: providing anelectrostatic sensing device comprising an electrostatic sensing modulecomprising a plurality of first electrostatic sensing elements, and acontrol unit electrically connected to the electrostatic sensing module,wherein the plurality of first electrostatic sensing elements is spacedand parallel to each other in same interval on a same plane, and each ofthe plurality of first electrostatic sensing elements is just onesingle-walled carbon nanotube or just one few-walled carbon nanotubewith two walls to six walls; applying a direct voltage to the pluralityof first electrostatic sensing elements; and measuring resistancechanged values of the plurality of first electrostatic sensing elementsin response to the sensed object, with electrostatic charge, being nearbut not making contact with the plurality of first electrostatic sensingelements, wherein a distance between the sensed object and the pluralityof first electrostatic sensing elements is less than 0.5 centimeter. 12.The method as claimed in claim 11, wherein the electrostatic sensingmodule comprises a substrate, and the plurality of first electrostaticsensing elements is located on a surface of the substrate.
 13. Themethod as claimed in claim 11, wherein the direct voltage is applied tothe plurality of first electrostatic sensing elements in sequence orsimultaneously.
 14. The method as claimed in claim 13, whereinresistance changed value of each of the plurality of first electrostaticsensing elements is proportional to the distance from the sensed objectto each of plurality of first electrostatic sensing elements.
 15. Themethod as claimed in claim 14, wherein a location of the sensed objectalong a direction perpendicular to the plurality of first electrostaticsensing elements is determined by one of the plurality of firstelectrostatic sensing elements with largest resistance changed value.16. An electrostatic sensing method for detecting a sensed object,comprising steps of: providing an electrostatic sensing devicecomprising an electrostatic sensing module and a control unitelectrically connected to the electrostatic sensing module, wherein theelectrostatic sensing module comprises a substrate, a plurality of firstelectrostatic sensing elements and a plurality of second electrostaticsensing elements located on a surface of the substrate intersected witheach other; the plurality of first electrostatic sensing elements isspaced and parallel to each other in same interval along a firstdirection X, the plurality of second electrostatic sensing elements isspaced and substantially parallel to each other in same interval along asecond direction Y perpendicular to the first direction X, each of theplurality of first electrostatic sensing elements and the plurality ofsecond electrostatic sensing elements is just one single-walled carbonnanotube or just one few-walled carbon nanotube with two walls to sixwalls; applying a direct voltage to the plurality of first electrostaticsensing elements and the plurality of second electrostatic sensingelements; and measuring resistance changed values of the plurality offirst electrostatic sensing elements and the plurality of secondelectrostatic sensing elements in response to the sensed object, withelectrostatic charge, being near but not making contact with theplurality of first electrostatic sensing elements and the plurality ofsecond electrostatic sensing elements, wherein a distance between thesensed object and the plurality of first electrostatic sensing elementsand the plurality of second electrostatic sensing elements is less than0.5 centimeter.
 17. The method as claimed in claim 16, wherein thedirect voltage is applied to the plurality of first electrostaticsensing elements and the plurality of second electrostatic sensingelements in sequence or simultaneously.
 18. The method as claimed inclaim 17, wherein resistance changed value of each of the plurality offirst electrostatic sensing elements is proportional to the distancefrom the sensed object to each of plurality of first electrostaticsensing elements, resistance changed value of each of the plurality ofsecond electrostatic sensing elements is proportional to the distancefrom the sensed object to each of plurality of second electrostaticsensing elements.
 19. The method as claimed in claim 18, wherein alocation of the sensed object along the first direction X is determinedby one of the plurality of first electrostatic sensing elements withlargest resistance changed value.
 20. The method as claimed in claim 18,wherein a location of the sensed object along the first direction Y isdetermined by one of the plurality of first electrostatic sensingelements with largest resistance changed value.